QPR face late competition from Nottingham Forest for the signing of Steve Cook.
A deal has been agreed in principle for the 30-year-old to move from Bournemouth and Rangers are looking to complete the transfer.
But Forest have also made an approach for Cook and are trying to persuade him to move to the City Ground.
Cook has made 388 appearances for the Cherries, featuring for them in the lower divisions and Premier League.
But he has been out of favour this season under boss Scott Parker and his contract expires in the summer.
He was not included in the matchday squad for Bournemouth’s recent win against the R’s because a move has been in the offing.
Mark Warburton told West London Sport earlier this month that he was keen to bring in an experienced centre-back.
Jordy de Wijs has been plagued by injuries since his move to the club and could be out until February with a calf problem.
Manager Warburton is therefore keen to add a centre-back to his squad and does not believe Conor Masterson would be the answer at this stage of the young defender’s career given that Rangers are in the thick of the Championship promotion race.
De Wijs, signed on a permanent deal during the summer, has not played since going off in the 1-1 draw against Nottingham Forest on 29 October – and has managed just 20 league starts during his 11 months at Rangers.
Warburton currently has other options in the centre of defence but one or two other injuries in addition to De Wijs’ propensity to miss matches could create a problem in a key area during a crucial stage of the campaign.
Masterson, 23, is on loan at Cambridge United until January and Warburton believes he should complete the season away from W12.
Warburton thinks highly of him but has long been keen for Masterson, who had no first-team experience prior to being signed in July last year after being released by Liverpool, to spend a significant period of time out on loan.
He has impressed when he has featured for QPR but just has 33 league starts to his name.
With the stakes so high for Rangers, who have a realistic chance of reaching the Premier League, Warburton wants a more seasoned defender to boost the squad.
“Young players need to go out on loan to develop,” Warburton said.
“Conor’s is a really good loan so far. He’s playing in League One week in, week out, and getting good experience. It’s great development for a young defender.
“Now, if QPR are in a good position and want to push, do we want a young defender and take him away from a good loan, or do we want to look at it and say that we may need to go into the market in January and get someone experienced to come in and add another level of quality to us?
“Are we just going to fill gaps or are we looking to push on?
“I think enormously of Conor, so that’s nothing derogatory in any shape or form.
“But a young defender has gone out on a perfect loan and is doing really well. I’m delighted to see it. He’s enjoying his football and getting experience.
“Do we change that? Do we spoil that loan? If it’s an emergency then we’ll do what we have to do for QPR. But right now, are QPR going to have a go, push, or are we happy to just try and fill holes and get jerseys on the pitch?”